1. Field of the Invention
This invention relates to bulldozer blade attachments, and more particularly to a set of ripping or raking teeth which may be secured to a bulldozer blade in either a deployed or undeployed position.
2. Description of the Prior Art
Bulldozers having a planar, vertically movable blade secured to their forward ends are commonly used in a variety of applications including ripping or raking in which a layer of rigid surfacing material is removed from an area, and grading in which the lower edge of the blade is scraped along a surface. During the ripping operation, ripping teeth have long been used to allow the blade to dig into the surfacing material. Although ripping teeth may be integrally formed with the lower edge of the blade, in most instances the teeth are individually bolted onto the lower edge of the blade to facilitate removal for the scraping operation and replacement of broken teeth. Although these teeth have generally proven somewhat satisfactory for a ripping operation, they suffer from a number of serious shortcomings. The principal disadvantage of bulldozer blades having conventional ripping teeth is the relatively large amount of time required to convert from a ripping blade to a scraping blade. During a ripping operation after the surfacing material has been broken into pieces, the pieces must be removed from a surface and the surface leveled. With the ripping teeth in conventional use, the teeth must be first removed from the blade or else a separate bulldozer must be used for the grading operation.
Another problem associated with conventional ripping teeth is their inability to withstand rearward forces without fracturing. The ripping teeth generally project forwardly and downwardly from the lower edge of the bulldozer blade and are thus extremely sturdy in receiving forces from in front of the blade since these forces act along the axis of the teeth. However, forces imparted to the teeth from a rearward direction, such as when the bulldozer is moving in a reverse direction with the blade down, produce a force transverse to the longitudinal axis of the teeth which can easily fracture the teeth--thereby necessitating time consuming and expensive replacement. In summary, although conventional ripping teeth are generally satisfactory, they require an excessive period of time to convert from a ripping blade to a scraping blade, and they are not sufficiently resistant to fracture by rearward forces.
Structures have been previously devised for pivotally securing a plurality of elongated members to a bulldozer blade. Examples of such devices are illustrated in U.S. Pat. Nos. 2,132,261; 3,097,439; and 3,595,416. However, these devices are not utilized to easily and quickly convert a conventional bulldozer blade to a ripping blade, and they lack features which are essential for achieving this function. For example, none of the prior art structures include means for positioning the elongated members so that they will not interfere with the use of the blade in a conventional manner.